Presently known chemical mechanical polishing machines typically employ either a single carrier or a plurality of carriers, each configured to hold a single semiconductor wafer firmly against a polishing surface, for example the upper surface of a rotating polishing pad. As a result of the relative motion between the semiconductor wafer surface to be polished and the polishing pad, coupled with the downward pressure applied by the wafer carrier to press the wafer against the polishing pad, even very small deviations in the uniformity of the pressure applied to the semiconductor wafer across the wafer surface can result in imperfections in the planarization process. In order to maintain a uniform pressure to the semiconductor wafer, current carriers often comprise a flexible membrane, or bladder, that covers a downward opening on the underside of a carrier thereby creating a space between the carrier and the bladder. An idealized bladder system expands or translates primarily in the axis of the wafer. When a pressurized fluid is applied to the space, the bladder applies a uniform downward pressure across the entire upper surface of a wafer that is being polished. One example of such a carrier can be found in U.S. Pat. No. 5,449,316 issued to Strasbaugh.
Although current carriers employing a bladder enable uniformity, carrier to carrier identicalness is a problem. Further, current carrier designs employing a bladder have a high cost of ownership due to several factors relating to lifetime of the carrier and replacement costs of the carrier such as downtime, wear on the retaining ring, ring delamination, part fatigue, assembly reproducibility and difficulty in assembling the carriers. In addition, current carriers employ adhesives and/or compressive joints which can fail as a result of too much pressure and vacuum cycling in a wet corrosive environment.
Accordingly, there is a need for a reliable bladder carrier that is cost efficient and time efficient. There is also a need for a method for making such a bladder carrier that further reduces cost of ownership.